A wide reciever and flex question....

So, I have Mike Wallace and Steve Johnson as starters. I subbed Lance Moore in for Johnson, and am considering Mike Williams from Seattle in place of Wallace. I also have a flex position open with Chris Ivory, Reggie Bush, Pierre Thomas, Rashad Jennings, or any of the above mentioned recievers available for it. I was leaning towards Thomas, but him returning kicks gives me a small concern that it may limit his touches on offense. Any thoughts?